Premium
THE RATE TEST OF SPECIATION: ESTIMATING THE LIKELIHOOD OF NON‐ALLOPATRIC SPECIATION FROM REPRODUCTIVE ISOLATION RATES IN DROSOPHILA
Author(s) -
Yukilevich Roman
Publication year - 2014
Publication title -
evolution
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.84
H-Index - 199
eISSN - 1558-5646
pISSN - 0014-3820
DOI - 10.1111/evo.12326
Subject(s) - allopatric speciation , sympatry , sympatric speciation , parapatric speciation , biology , genetic algorithm , reproductive isolation , ecological speciation , evolutionary biology , incipient speciation , zoology , ecology , population , genetics , gene flow , genetic variation , demography , sociology , gene
Among the most debated subjects in speciation is the question of its mode. Although allopatric (geographical) speciation is assumed the null model, the importance of parapatric and sympatric speciation is extremely difficult to assess and remains controversial. Here I develop a novel approach to distinguish these modes of speciation by studying the evolution of reproductive isolation ( RI ) among taxa. I focus on the Drosophila genus, for which measures of RI are known. First, I incorporate RI into age‐range correlations. Plots show that almost all cases of weak RI are between allopatric taxa whereas sympatric taxa have strong RI . This either implies that most reproductive isolation ( RI ) was initiated in allopatry or that RI evolves too rapidly in sympatry to be captured at incipient stages. To distinguish between these explanations, I develop a new “rate test of speciation” that estimates the likelihood of non‐allopatric speciation given the distribution of RI rates in allopatry versus sympatry. Most sympatric taxa were found to have likely initiated RI in allopatry. However, two putative candidate species pairs for non‐allopatric speciation were identified (5% of known Drosophila ). In total, this study shows how using RI measures can greatly inform us about the geographical mode of speciation in nature.